Strand treatment process and apparatus



Nov. 19, 1968 M. F. IRWIN 3,411,192

STRANDYTREATMENT PROCESS AND APPARATUS Filed Dec. 12, 1966 awn/m M41601 E MW/A/ Arron 5m United States Patent 3 411 192 STRAND TREATMENT PRocEss AND APPARATUS Malcolm F. Irwin, Philadelphia, Pa., assignor to Techniservice Corporation, Lester, Pa., a corporation of Pennsylvania Filed Dec. 12, 1966, Ser. No. 600,977 20 Claims. (Cl. 28-1) This invention relates to treatment of textile strands, especially the aftertreatment of crimped textile strands by essentially non-slipping contact with a resilient surface.

Crimped strand is withdrawn from the zone in which it was crimped and is passed between the nip of a pair of rolls, one or both of them having a resilient surface. When passing through the roll nip the strand should be hot, i.e., well above room temperature, but below the softening temperature of the strand composition.

This invention is described and illustrated with particular reference to stutter-crimped strands. Procedures for stutter-crimping textile strands are well known in the art, having been described, for example, in Pat. 3,027,619 and patents cited therein. Required are a temporarily confining chamber to provide the strand-crimping zone, and a pair of nip rolls or equivalent means at the entrance end of the chamber to feed or stuff thereinto the strand to be crimped therein. Various devices for applying backpressure to the resulting compact accumulation of strand in the chamber are also known, and any of them may be used if desired but, as they form no part of the present invention, will not be dealt with further herein.

A defect often, if not invariably, encountered in crimped strands of the prior art is instability of the crimp often manifested as a reduction in amount of crimp, whether determined by measurement of crimp angle, strand bulk, or otherwise, especially as the crimped strand was subjected to further handling, winding operations, or miscellaneous tensioning. Attempts have been made to counteract such defect by intentionally reducing the crimp level somewhat as a crimping afteitreatment, but it is difficult to do so without introducing other undesirable irregularities, and the resulting reduction in crimp level often is undesirable.

A primary object of the present invention is stabilization of crimp in crimped textile strands without reduction in crimp level.

Another object is reduction in the extensibility of crimped textile strand without appreciable effect upon the crimp level thereof.

A further object is reduction in unevenness of crimp level in stuffer-crimped textile strands.

Other objects of the present invention, together with means and methods for attaining the various objects, will be apparent from the description herein and the accompanying diagrams.

FIG. 1 is a side elevation, partly schematic of apparatus practicing the present invention;

FIG. 2 is a sectional view of certain components of the apparatus of FIG. 1;

FIG. 3 is a like view of a modification of the portion of the apparatus shown in FIG. 2;

FIG. 4 is a side elevation, partly schematic and partly in section, of a modification of the apparatus of FIG. 1;

FIG. 5 is a schematic side elevation of certain of the components of FIG. 1 together with heating means; and

FIG. 6 is a schematic side elevation of certain other components of preceding views together with heating means.

In general, the objects of the present invention are accomplished by passing crimped textile strand, after its passage through a stuffer-crimping zone, into essentially non-slipping contact with a resilient surface, as by passing it through the nip of a pair of nip rolls at least one of which is resilient. As further indicated herein the strand may be preheated or even heated by the last mentioned rolls. In any event it is desirable that the strand be hot when passing through the roll nip, not so hot as to approach the softening temperature of the strand composition but well above ordinary room temperature.

FIG. 1 shows strand 10 being withdrawn from supply package 11 thereof by pair of feed rolls 12, 12' through whose nip it passes and by Which it is fed into the entrance end of chamber 13, shown somewhat schematically and extending horizontally from end to end. Upon encountering the compact accumulation of crimped strand (not shown but discussed above) already therein the strand buckles into the characteristic sawtooth or Zigzag crimped configuration, indicated schematically as strand 10 being withdrawn from the opposite end of the compact strand accumulation and out of the exit end of the chamber.

Crimped strand 10' passes through the nip of pair of rolls 22, 22' and partway (shown as halfway) about the latter roll and is wound onto takeup package 21, which is pivotally supported on swing arm 23 and is rotated about its mounting point on the swing arm by surface contact with drive roll 24, which may be of the well known self-traversing type. The drive roll is driven by motor M, which is also adapted to (but need not) be connected (interconnections therewith being shown in dashed lines) to drive, at an appropriate surface speed, roll 22 through disengageable transmission 25, of conventional type.

According to this invention, either or both of nip rolls 22, 22 should have a resilient surface, as shown in FIGS. 2 and 3, respectively. This may be accomplished by surrounding a metallic cylindrical core with a layer of natural or synthetic rubber or other elastomeric composition. The resilience thereof should be such that when only one resilient roll is used it should give a lower durometer reading than is obtained when a pair of resilient rolls is used. The resilience of the rolls also may be varied depending upon the denier of the strand being treated thereby so as to provide equivalent lateral force on the strand. The rolls are set to touch one another with no more than slight deformation of the surface of the resilient roll or rolls at the nip.

In such aftertreatment of stutter-crimped nylon multifilament strands having a total denier in the range of from somewhat under one thousand and somewhat over two thousand, denier per filament being between ten and twenty, a pair of resilient rolls composed of synthetic rubber and having a durometer hardness of have proved quite satisfactory. The strands were treated at temperatures well above room temperature but below the softening temperature of the nylon. Treating temperatures in the range of from about C. to C. gave good results. The nylon used melts at about 250 C. and softens appreciably 25 to 50 degrees below the melting temperature.

The preferred hot condition of the crimped strand being treated may be brought about by heating the strand at any time theretofore or even at or by the treating rolls. It is preferred to heat the strand before crimping it, as by heating one of the feed rolls either internally or (as shown in FIG. 5) by juxtaposition of external electric resistance heating block 32, for example, to the surface of one of the feed rolls. One of the treating rolls also may be heated, as by similar heating block 32", either instead of or in addition to heating of a feed roll or the chamber. If the strand is preheated it is useful to surround the hot crimped strand exiting from the chamber to prevent chilling thereof before reaching the treating rolls, as by insulated tubular member 33 therebetween, which is shown in FIG. 4 and may constitute an extension of the chamber. Such tubular member is cut away at one end to show tubular insulating layer 34 and surrounding metal jacket 35 thereof. The chamber may be similarly composed if desired.

The strand may be withdrawn from the chamber by positive rotation of the rolls, if desired, or they may be free-running in which event the windup drive roll may apply the desired withdrawing force. The apparatus connections for both such arrangements have been described above. If both the Windup and treating rolls are positively rotated, their surface speeds should be essentially the same, as may be accomplished by means of the indicated transmission. Of course, such speed is appreciably less than the surface speed of the feed rolls, in accordance with the effective reduction in strand length attributable to the crimping thereof. The infeed and windup speeds can be synchronized in conventional manner, as may be desirable.

Strand treated according to this invention exhibits reduced extensibility under load but Without appreciable change in crimp level, as determined by tests customarily used in the art. This means that no partial de-crimping step need be added to provide acceptable or improved crimp stability and that essentially the entire crimp imparted to the strand can be maintained throughout conventional handling and textile operations. Resulting advantages in customer satisfaction, economy of operation, and otherwise will be apparent to those skilled in the art. Although the invention has been described with reference to a preferred embodiment and certain modifications thereof, it will also be apparent that other changes may be made, as by adding, combining, or subdividing parts or steps, while maintaining at least some of the advantages and without involving a departure from the inventive concept.

What is claimed is:

1. In stutter-crimping of textile strands the improvement comprising stabilizing crimped strand by passing the crimped strand, after its passage through a stutter-crimping zone, through the nip of a pair of nip rolls at least one of which is resilient, whereby the crimped strand is stabilized without reduction in crimp level.

2. The process improvement of claim 1 wherein both nip rolls are resilient.

3. The process improvement of claim 1 wherein the crimped strand is passed through the roll nip upon being withdrawn from the crimping zone.

4. The process improvement of claim 3 wherein the nip rolls are free-running.

5. The process improvement of claim 3 wherein the crimped strand is withdrawn from the crimping zone by the nip rolls.

6. The process improvement of claim 1 wherein the crimped strand passes at least about halfway around one of the nip rolls.

7. The process improvement of claim 6 wherein the crimped strand passes at least about halfway around one of the nip rolls after passing through the roll nip.

8. The process improvement of claim 7 wherein the crimped strand is wound onto a package after passing at least about halfway around one of the nip rolls.

9. The process improvement of claim 1 wherein the nip rolls are hot.

10. The process improvement of claim 9 wherein the roll temperature is within about C. below the softening temperature of the strand composition.

11. The process improvement of claim 9 wherein the strand path from the crimping zone to the nip rolls is insulated against heat loss.

12. The process improvement of claim 9 wherein the nip rolls are heated solely by contact with the crimped strand.

13. Strand-treating apparatus comprising a stuttercrimper and stabilization means located to receive crimped strand therefrom comprising a pair of nip rolls, at least one of which is resilient, whereby said means is adapted to stabilize the crimped strand without reduction in crimp level.

14. The apparatus of claim 13 wherein both nip rolls are resilient.

15. The apparatus of claim 13 comprising means other than the nip rolls for withdrawing crimped strand from the stuffer crimper.

16. The apparatus of claim 13 wherein the nip rolls comprise means for withdrawing crimped strand from the stutter crimper.

17. The apparatus of claim 16 including means for rotating at least one of the nip rolls.

18. The apparatus of claim 13 including means for heating at least a portion of the stuflfer crimper.

19. The apparatus of claim 18 including means for insulating against heat loss the path of the crimped strand from the stutter crimper to the nip rolls.

20. The apparatus of claim 13 including means for heating at least a portion of the nip rolls.

References Cited UNITED STATES PATENTS 3,032,829 5/1962 Mahoney et al 1916 X 3,147,533 9/1964 Baer 28-1 3,152,379 10/1964 Osban 281 3,177,556 4/1965 Van Blerk 28-72 3,259,953 7/1966 Baer 28l LOUIS K: RIMRODT, Primary Examiner. 

13. STRAND-TREATING APPARATUS COMPRISING A STUFFERCRIMPER AND STABLIZATION MEANS LOCATED TO RECEIVE CRIMPED STRAND THEREFROM COMPRISING A PAIR OF NIP ROLLS, AT LEAST ONE OF WHICH IS RESILIENT, WHEREBY SAID MEANS IS ADAPTED TO STABILIZE THE CRIMPED STRAND WITHOUT REDUCTION IN CRIMP LEVEL. 